CVE-2021-31375Junos OS: Receipt of a specific BGP update may cause RPKI policy-checks to be bypassed
- 7.2HighCVSS base score
- 0.80%Exploitation in 30 daysEPSS · top 43% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
An Improper Input Validation vulnerability in routing process daemon (RPD) of Juniper Networks Junos OS devices configured with BGP origin validation using Resource Public Key Infrastructure (RPKI), allows an attacker to send a specific BGP update which may cause RPKI policy-checks to be bypassed. This, in turn, may allow a spoofed advertisement to be accepted or propagated. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S18; 15.1 versions prior to 15.1R7-S9; 17.2 versions prior to 17.2R3-S3; 17.3 versions prior to 17.3R3-S7; 17.4 versions prior to 17.4R2-S9, 17.4R3; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S3; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R2; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2.
Timeline
ID reserved
By juniper
- 6 months later
· 6 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | High7.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L |
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.80% · top 43% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.2.
Affected products
- affected 12.3 – < 12.3R12-S18
- affected 15.1 – < 15.1R7-S9
- affected 17.2 – < 17.2R3-S3
- affected 17.3 – < 17.3R3-S7
- affected 17.4 – < 17.4R2-S9, 17.4R3
- affected 18.1 – < 18.1R3-S13
- affected 18.2 – < 18.2R3-S3
- affected 18.3 – < 18.3R3-S1
- affected 18.4 – < 18.4R3
- affected 19.1 – < 19.1R2
- affected 19.2 – < 19.2R2
- affected 19.3 – < 19.3R2
What to do
Solution: The following software releases have been updated to resolve this specific issue: 12.3R12-S18, 15.1R7-S9, 17.2R3-S3, 17.3R3-S7, 17.4R2-S9, 17.4R3, 18.1R3-S13, 18.2R3-S3, 18.3R3-S1, 18.4R3, 19.1R2, 19.2R2, 19.3R2, 19.4R1, and all subsequent releases.
Workaround: There are no viable workarounds for this issue.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References
References1
- https://kb.juniper.net/JSA11240 (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-18285 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-31375)Record last updated .